Sampling pump for use in bore holes



R. H. BLOOD 2,831,439

SAMPLING PUMP FOR USE IN BORE HOLES 2 Sheets-Sheet 1 A ril 22, 1958Filed Nov. 2'7, 1953 FIG.I

ROBERT H. BLOO D BY ATTORNEY April 22, 1958 R. H. BLOOD SAMPLING PUMPFOR USE IN BORE HOLES 2 Sheets-Sheet 2 Filed Nov. 27, 1953 F IG.4

INVENTOR ROBERT H.BL OD ATTORNEY United States Parent O SANlPLING PUlVIPFOR USE IN BORE HOLES Robert H. Blood, Tulsa, Okla., assignor to EssoResearch and Engineering Company, a corporation of Delaware ApplicationNovember 27, 1953, Serial No. 394,661

S Claims. (Cl. 103-181) This invention is primarily concerned with apump for use in bore holes employed in the exploration for andproduction of petroleum from the earth. The pump of this invention isoperative as a wire line supported pump and may be used in a widevariety of applications for obtaining samples of fluid from a bore holeor from formations adjacent the bore hole. The particular feature ofthis invention is the provision of a down-the-hole force pump which canetfectively be used to force fluids from any depth in a bore hole undervirtually any pressure to the surface of the earth. In one embodiment ofthe invention, use of this pump is particularly attractive withformation testers in order to force fluid from strata adjacent the borehole to the surface of the earth.

ln drilling a bore hole in the attempt to discover oil (leposits in theearth, it is important at various stages of the procedure to determinethe composition of fluids present in the bore hole. This problem iscomplicated by the fact that so-called "drilling mud" is ordinarilypresent in the hole so that it is desirable to isolate fluids producedin the bore hole from the drilling mud which is present. Because of thefact that the drilling mud is l used to maintain a high hydrostaticpressure within the bore hole, it also follows that production of uidsfor testing purposes from low pressure producing zones adjacent the borehole is also diflicult. i

Apparatus known as formation testers" are employed for the purpose ofsampling fluids which may be produced at a bore hole. Formation testersare known and used of many different types. One of the most attractiveforms of such testers is the type employing an inflatable elastc packerwhich can be inflated to seal off a portion of the bore hole. In somecases two such packers are employed so that fluid can be producedbetween the packers while keeping out drilling mud otherwise present inthe hole. In other cases suitable fluid sampling passages may beprovided through a portion of the inflatable packer itself. in any case,it is necessary to make some provision for the passage of fluid fromstrata adjacent the bore hole into a sample chamber or through the drillstring so as to maintain this fluid separate from drilling mud in thebore hole to the extent possible.

While fluid may be produced from a formation in this general manner forrecovery in a sample chamber associated with the formation tester, thisis subject to the real disadvantage that the Volume of a sample chamberby its nature is comparatively limited. Again, it is difficut to preventat least some contamination ot the sampled fluid with drilling mud inthe fillingof a sample chamber. 'It has also been appreciated that fluidmay be sampled from formations by pumping out the drilling mud in thedrill string leading to the formation tester so that produced fluid canbe brought to the surface of the earth. However, in the case in which avacuum pump is employed for this purpose at the surface of the earth,the maximum pressure diflerential which can be developed to produce thisfluid is a head of some thirty feet of water.

-2,83,439 Patented Apr. 22, 1958 This limitation makes it impractical tosuitably produce fluids from low pressure producing zones adjacent 'thebore hole. Swabbng techniques which are employed are subject to thedisadvantage that large quantities of fluid must be removed beforeproduction of fluid can begin from low pressure producing strata.

It is the purpose of this invention to provide an ap paratus which willsatisfy the objectives indicated in the foregoing discussion. Thus, one'of the principal objects of this invention is to provide adown-the-hole force pump which can be used to successfully force sampledfluid to the surface of the earth without the limitations of a vacuumpump employed at the surface of the earth. lt is another object of thisinvention to provide a wire line Suspended and operated pump which canbe used for obtaining a sample of fluid from any level in a bore hole.These and other benefits of this invention will become apparent from thefollowing description of a preferred form of the invention. In thisdescription reference will be made to the accompanying drawings, inwhich:

Figures and 2 taken together illustrate in cross-seu tional, elevatonaldetail the operative features of a basic pump ernbodying the piinciplesof this invention. In these figures, Figure 1 illustrates the uppersection of the pump assembly, while Figure 2 illustrates the lowercontinuation of the pump;

Figure 3 srnilarly illustrates in cross-sectional, elevational detailthe upper portion of the pump assembly of Figure 1 illustrating theposition of the pump elements during suspension on the wire line;

Figura 4 is a fragmental cross-sectional, elevational drawing of thelower portion of the pump showing a variation of the invention in whicha shear pin is used to lock the piston of the pump with respect to theptunp cylinder;

Figura 5 is a cross-section view of the apparatus of Figure 2 takenalong the section lines V-V in Figure 2.

Referring to Figures l and 2, the pump of this invention is illustratedin operative pumpirg position within a casing or a drill string 2positioned in a bore hole. The pump primarily comprises two majorelements; the pump barrel or cylinder 3 and the tubular piston element4. The piston 4 may constitute a cylinder as illustrated in order toprovide a central passage 5 through which fluid can pass. As shown, thepassage 5 terminates at the upper end of the piston in ports 32 adjacentthe point of suspension of the piston by the wire line or cable 6. Thelower termnation of the passage 5 is provided with a check valvearrangement 7, which is employed to permit the flow of fluid upwardlythrough passage 5 but 'to prevent flow of fluid downwardly throughpassage 5. For this purpose the simple ball check valve arrangementshown may be employed, in which a spider 8 or a similar provison is madefor retaining the ball of the check valve adjacent the valve orifice 9without preventing flow of fluid upwardly through the spider 8. A cupseal 10 may be employed at one or more positions along the piston so asto secured efiective fluid displacement as the piston is pulled upwardlywithin the cylinder 3, but permitting the piston to move downwardlywithout undue restriction. I

The pump barrel 3 is also provided with a cup packer arrangement 12 atan upper portion thereof so as to prevent the flow of fluid downwardlyin the annulus 25 between the drill string 2 and the pump barrel 3.Packer 12 is of a character permitting the pump cylinder to slide withinthe drill string 2 and may permit fluid to pass upwardly about thepacker, although, as stated, flow of fluid downwardly past the cuppacker is prevented. It is an important feature of this invention toprovide means to bypass fluid about the cup packer 12, and for this parpose a number of orifices 13 and 14 are drilled through the pump burrelabove and below the cup packer 12. These orifices are arranged toregister with a slide valve 15 when the valve 15 is placed in theposition illustratcd in Figure 3, permitting fluid to bypass the packer12. During operation of the pump, slide valve 15' is held in a positionto prevent fluid flow through orifices 13 and 14 by action of the spring16, vhich forces the slide valve 15 into the downward orclosed positionillustrated in Figure 1. The slide valve 15 may be provided with seals1"? in order to seal the slide valve within the pump cylinder 3.

In the embodiment of the pump illustrated in Figures l and 2, it isimportant to provide some means to limit the downward position of thepump cylinder 3 with respect to the drill string 2. As illustrated inFigure 2, this may be accomplished by providing a shoulder 18 within thedrill string 2 on which the lower termination of the pump cylinder mayrest. The lower end of the pump cylinder 3 is fluted or otherwiseprovided with one or more fluid passageways 24 to provide fluidcommunication between the portion of the drill string 2 below shoulder18 and the annulus 25 between the drill string and the pump cylinder. Itis an optional feature of the. invention to employ a pressure recorder19 which is preferably positioned within the lower portion of the pumpcylinder 3 or an extension thereof. A suitable pressure recorder isdiagrammatically illustrated including spider arrangements 20 and 21 forpositioning the pressure recorder within the pump barrel 3. It isnecessary to provide a check valve at a lower portion of the pumpcylinder of a nature to permit fluid flow upwardly within the pumpcylinder but to prevent fluid flow downwardly out of the pump cylinder.This can be simply achieved by employing a ball type check valve 22 atthe lowermost portion of the pump cylinder.

From this description of the essential elements of the pump illustratedin Figures 1, 2 and 3, the operation of this device can now beunderstood. For the purpose of this description, it can be assumed thatthe cut-away portion of the drill string 2 at the bottom of Figure 2 isconnected with a suitable formation tester. For example, a formationtester of the character disclosed and claimed in U. S. Patent 2,600,173,issucd to Ben W. Sewell et al. on June 10, 1952, may be employed. In theevent this type of formation tester is employed. the lower terminationof the drill string 2 illustrated in Figure 2 of this patent may connectwith the drill string S illustrated in the drawings of the Sewell et al.patent. lt will therefore be understood that fluid which can be obtainedfrom a formation to be tested will have access to the pump cylinder 3 ofthis invention through the check valve arrangement 22.

After the formation tester identified, or any other desired type offormation tester, is placed in operative position within a bore hole,the wire line pump of this invention is lowered into the drill string bymeans of the cable 6. During the lowering operation, the pisten tof thepump will be held upwardly against slide valve 15 so as to hold theslide valve in the position shown in Figure 3. Since the entire Weightof the pump will be horne by the piston through the cable suspension, itis apparent that spring 16 can be compressed during the loweringoperation to maintain the slide valve 15 in the indicated position. Inthe position of the slide valve 15 illustrated in Figure 3, fluid canreadily pass from the annulus within the drill string 2 so as to bypassthe packer 12. The fluid will flow through the orifices 13 through slidevalve 15 and through oriflces 14. It is also apparent that fluid willhave a course of flow upwardly through the check valve 22 through thelower portion of the pump burrel 3, through check valve 7, through thepassage 5 of the piston 4, through the central opening of the slidevalve 15, and through the upper port 23 of the pump cylinder.Consequently, movement of the entire pump assembly'will not be impededas the pump is lowered into the drilling mud or other fluid present inthe drill string.

When the pump has been lowered to contact the shoulder 18 within thedrill string 2, the pump cylinder will be locked with respect to thedrill string Thereafter, continued lowering of the cable 6 will permitthe piston 4 to slide within the pump cylinder to the downward limit ofmovement with respect to the pump cylinder. This will permit the spring16 to force slide valve 15 into the downward and closed positionillustrated in Figure l so as to close oli fluid flow through ports 13and 14. The pump is then in operative position for use.

Pumping action is achieved by raising and lowering the cable 6 withinsuitable limits of movement. Thus, for example, suitable means may beused to limit the rotation of the cable winch so that during strokingthe piston 4 will not contact or alter the position of slide valve 15.On each upward stroke of the pisten, check valve 7 will close so thatfluid trapped above the check valve within the passage 5 of the pistonand within the pump cylinder will be forced upwardly. During the upwardstroke of the pisten, fluid will also enter the lower portion of thepump cylinder through the check valve 22 so as to replace that fluidpumped upwardly by the piston. On the downward stroke of the pisten,check valve 22 will close preventing escape of fluid downwardly from thepump barrel and permitting this fluid to pass upwardly through checkvalve 9 into the piston and upper portion of the pump cylinder. In thismanner continuous pumping action can be carried out to force any desiredquantity of fluid upwardly through the drill string 2.

It will be apparent that the cup packer 12 positioned about the upperportion of the pump cylinder 3 provides an important function duringpumping. lnitiation of the pumping action reduces the pressure below cupseal 12 with respect to the pressure above the cup seal 12 so that thispressure differential tightly seals the packer against the drill stringZ and serves to hold down the pump cylinder in the operative positionshown in Figures l and 2.

While operation of the pump has been described in connection Withcontinuous pumping action for displacing considerable volumes of fluidupwardly through the bore hole, if desired, single stroke action of thepump may be employed. In this case the pump itself can be used as asample chamber for produced fluid. Thus, after the pump has been loweredto the operative position within the drill string 2, an Upward stroke ofthe piston 4 will serve to bring fluid within the pump cylinder. Whenthe pump is then pulled to the surface of the earth, this fluid will betrapped within the pump cylinder by action of the difierent check valvesso that the fluid can be recovered when the pump is retrieved at thesurface of the earth.

For removal of the pump from the drill string, the slide valve 15inherently operates to eliminate the pressure differential across thecup packer 12 so as to permit unrestricted removal of the pump from thedrill string. This is accomplished when the cable 6 is reeled in sincethe piston 4 will be forced upwardly against slide valve 15 to move thevalve into the position shown in Figure 3. Fluid can then bypass the cuppacker 12 through orifices 13 and 14 so that the entire pump assemblycan readily be pulled from the drill string.

The pump described may be employed in widely different manners in orderto sample fluid from a bore hol. For example, the pump may be used tosample the fluid present in a bore hole at any given level withoutnecessity for using the shoulder or other supporting means within thedrill string. In this case, the arrangement shown in Figure 4 may beused to obviate necessity for including provision for limiting thedownward movement of a pump barrel with respect to the drill string. Asshown in Figure 4, a shear pin 31 may be passed through the lowerportion of the pump barrel 3 into the lower portion of selected level inthe drill string, an upward pull on cable 6 will serve to break shearpin 31, due -to the fact that the weight of the drilling mud actingthrough the pump seal 12 will provide sufiicient shearing stress tobreak shear pin 31. Therefore, the piston 4 will be moved upwardly withrespect to the pump barrel 3 so as to pump fluid within the pumpcylinder. As formerly indicated, this fluid will remain trapped withinthe pump barrel until the pump can be removed at the surface of theearth.

Again, while the invention has been described with reference to the useof a drill string 2 in a bore hole, it is apparent that the pumpassembly can be used in an open bore hole if desired. In this use of theinvention, the cup packer 12 must be of a nature to effectively sealagainst the open bore hole. Packers of this nature are known to the artand may include, for example, a plurality of upwardly extending elasticskirt members. Such seals may be successfully employed in an open borehole provided they are of reasonably regular gauge.

if desired, the pump assembly can also be provided with suitablereleasable latching means to lock the pump barrel at any desired levelin an open bore hole. Such releasable latching means may be used toreplace the function of the shoulder 18 illustrated in Figure 2.

To further indicate the scope of use for this invention, it is apparentthat while the invention has been described for use with a formationtester, in some cases the pump assembly by itself can function as aformation tester. Thus, for example, the pump itself can be used as abottom hole formation tester since the cup packer 12 serves to preventdrilling mud contamination of fluid produced below the packer and sincethe pump will function to force fluid produced below the pump assemblyupwardly to the surface of the earth.

The configuration of the different elements of the pump may be varied asdesired for design purposes. However, it is particularly preferred thatboth the piston 4 and the pump barrel 3 constitute elongated, massiveelements. This is desirable so that the mass of the apparatus willpermit ready lowering of the apparatus through the drilling mud presentin the bore hole. Again, by making the pump of substantial length, thesingle stroke use of the pump may be used to trap a substantial volumeof fluid for sampling purposes.

What is claimed is:

1. A pump apparatus comprisng in combination: an elongated pumpcylinder, a packing element about the upper periphery of said cylinder,a first and second orifice passing through said cylinder above and belowsaid packing element, a slide valve slidably positioned within the upperportion of the cylinder adapted to move to an open position establishingregister with said first and second orifices to permit fluid flowtherethrough, means to bias said slide valve to a closed positionpreventing the said fluid flow, a piston slidably positioned within saidcylinder having a channel passing completely through the piston, a checkvalve positioned in said channel permitting unidirectional flow throughthe piston, a check valve positioned in said cylinder permittingunidirectional flow into said cylinder from a region exterior of saidcylinder.

2. The pump defined by claim 1 wherein said slide valve is engageable bysaid piston when said piston is moved to the upper portion of saidcylinder and wherein an opening is provided through the top of saidcylinder to receive a supporting cable attachable to said piston wherebywhen the weight of the pump is supported by the cable the piston willurge said slide valve to its open position against said bias.

'3. A pump for use within a vertically disposed passage- Way whichcomprises a vertically disposed pump cylinder lowerable within saidpassageway and defining an annulus therebetween, check valve means inthe lower end of said cylinder to enable fluids to flow selectively intothe cylinder, a packer positioned on the exterior surface of saidcylinder to block fluid flow along said annulus, orifices extendingthrough the wall of said cylinder above and below said packer, valvemeans within said cylinder operable with said orifices in a first valveposition to cstablsh fluid communication around said packer and in asecond valve position to block fluid communication around said packer, apiston element movably disposed within said cylinder, a fluid channelextending vertically through said piston, and second check valve meansin said channel operable to enable fluid to flow selectively upwardlythrough said channel.

4. A wire-line operable, deep-well `pump which comprises a pump cylinderadapted to be lowered in a vertical disposition within a well, checkvalve means in the lower end of said cylinder operable to enable fluidto flow selectively into said cylinder, a packer positioned around andnear the upper end of said cylinder and operable to block downward flowof fluid in the annulus between the cylinder and the wall of the well, afirst orifice through the cylinder wall above said packer, a secondorifice through the cylinder wall below said packer, valve means withinsaid cylinder operable in a first open position to establish fluidcommunication between said orifices and in a second closed position toblock fluid comnunication therebetween, means biasing said valve meansin a normally closed position, a wire-line operable piston within saidcylinder, and combination port and check'valve means within said pistonoperable to enable fluid to flow selectively upward through said piston.

5. A pump adapted to be lowered and operated within a Well whichcomprises a pump cylinder which is vertically disposed when within awell, a check valve in the lower end of said cylinder operable to enablefluid to enter the cylinder, a piston within said cylinder, combinationport and check valve means within said piston adapted to enable fluid toflow upward through said piston, a wire line attached to the upper endof said piston and extending through the upper end of the cylinder, apacker around the upper periphery of the cylinder of a character toeflect a fluid-fight seal against the wall of the well, a first orificepenetrating said cylinder above said packer, a second orifice penetratngsaid cylinder below said packer, a sleeve valve positioned within saidcylinder above said piston, said sleeve valve in an upper verticalposition operable to provide fluid communication between said orificesthrough said valve and in a lower vertical position to block fluidcommunication between said orifices, spring means above said sleevevalve biasing the valve normally to its lower vertical position, saidpiston at the upper end of its possible travel within said cylinderbeing adapted to urge said sleeve valve into its upper verticalOperating position against the action of said spring.

References Cited in the file of this patent UNITED STATES PATENTS532,()25 Chaffee Jan. 8, 1895 789,567 Robinson May 9, 1905 l,603,188Lemmon Oct. 12, 1926 1,713,808 Yerkes May 21, 1929 2,083,714 Keeler June15, 1937 2,402,886 Granger June 25, 1946 2,511,759 Williams June 13,1950 2,600,173 Sewell June 10, 1952

